Apparatus for applying indicia to webs of photographic paper or the like

ABSTRACT

A web of photographic paper is provided with indicia in the form of parallel grooves which are impressed into the rear side of the web by a reciprocable or pivotable ram- or wheel-shaped tool having one or more projections in the form of teeth, ribs or rings. The grooves are deep enough to be detectable by a needle, elastically mounted blade or other mechanical scanning means which cooperates with a transducer serving to produce signals for actuation of a device which severs the web between neighboring prints or for actuation of an evaluating circuit which receives a signal upon detection of the last print forming part of a customer order. The grooves extend at right angles to the longitudinal direction of the web. The projections of the tool can be heated to insure the formation of lasting grooves even if the web is caused to pass through one or more liquid baths before it reaches the scanning station.

United States Patent 1191 Weber et al.

[ 51 Sept. 30, 1975 [73] Assignee: Agfa-Gevaert Aktiengesellschaft,

Leverkusen, Germany 221 Filed: Sept. 19, 1973 211 Appl. 190.: 398,847

425/l74.6, 155, 289, 367, 374, 375, 385, 363. DIG. 200, DIG. 201, 143

[56] References Cited UNITED STATES PATENTS 2,849,752 9/1958 Leary425/385 X 2,960,722 11/1960 Freeman..... 425/164 2,967,328 l/l961 Shelbyet al. 4.25/164 3.421.455 1/1969 Werner 425/367 X 3,465,384 9/1969Barchi ct al. 425/363 X Ballard et a1. 425/385 X 3,553,787 l/l97l3.632.252 l/l972 Amberg et a1... 425/385 X 3,676,216 7/1972 Abitboul425/385 UX 3,768,946 10/1973 Matuschke 425/363 3,785,762 1/1974 Butzko425/289 Primary E.\'aminerRobert L. Spicer, Jr. Attorney, Agent, orFirm-Michael S. Striker [57] ABSTRACT A web of photographic paper isprovided with indicia in the form of parallel grooves which areimpressed into the rear side of the web by a reciprocable or pivotableramor wheel-shaped tool having one or more projections in the form ofteeth, ribs or rings. The grooves are deep enough to be detectable by aneedle, elastically mounted blade or other mechanical scanning meanswhich cooperates with a transducer serving to produce signals foractuation of a device which severs the web between neighboring prints orfor actuation of an evaluating circuit which receives a signal upondetection of the last print forming part of a customer order. Thegrooves extend at right angles to the longitudinal direction of the web.The projections of the tool can be heated to insure the formation oflasting grooves even if the web is caused to pass through one or moreliquid baths before it reaches the scanning station.

23 Claims, 13 Drawing Figures US. Patent Sept. 30,1975 Sheet10f6 v3,909,171

Fig. 2

US. Patent Sept. 30,1975 Sheet 2 of6 3,909,171

Fig. 4

US. Patent Sept. 30,1975 Sheet 3 of6 3,909,171

U.S. Patent Sept. 30,1975 Sheet4 of6 3,909,171

IZl lIa US. Patent Sept. 30,1975 Sheet 5 of 6' 3,909,171

h=4mm Fig.

r 1 m fa "a US. Patent Sept. 30,1975 Sheet 6 of6 3,909,171

BACKGROUND OF THE INVENTION The present invention relates to apparatusfor applying indicia to webs consisting of paper or other photographicfilm deformable material. More particularly,

the invention relates to apparatus for applying automatically detectableindicia to webs of interconnected photographic prints for the purpose ofinitiating the operation of severing devices, counters and/or othersignal responsive units in an automatic processing laboratory or thelike.

It is well known'to provide webs of interconnected prints with indiciain the form of graphite marks or notches which can be detected byphotoelectric or other scanning means serving to actuate cutting orsevering devices which subdivide the webs into discrete prints ready tobe shipped to customers and/or dealers. Certain indicia serve toindicate the end of acustomer order and/or the start of the next order.The position of each indicium with respect to the respective frame line(where the web is to be severed between two neighboring prints) is orshould be such thati'the signal which is generated in response todetection of an indicium can be amplified and transmitted to theactuating means for a severing device so that the latter can sever theweb across or close to the center of the respective frame line. I

The just discussed indicia are of considerable help in insuringautomatic or semiautomatic processing of films and/or prints in alaboratory, especially when the laboratory operates at maximum capacity(such as during and after the summer vacation period, following certainholidays and/or similar occasionswhen the customers send in ordeliverextremely large numbers of exposed films for processing andmaking of prints).

As a rule, the indicia are applied to the rear side of a web ofphotographic paper the front side of which is coated with aphotosensitive emulsion. Graphite marks are applied by a small wheelwhich is caused to contact the rear side of the web at intervalsdetermined by the spacing of exposed frames on the correspondingphotographic film. Such marks can be detected due to the fact that theirlight absorption is more pronounced than that ofthe unmarked portion ofthe rear side of the web and/or because their conductivity is differentfrom that of the material at the rear side of the web. As mentionedabove, such marks can be applied for the purpose of indicating the lociwhere a web is to be severed between neighboring prints and/or toindicate the last print of a particular customer order. I

A drawback of graphite marks is that they are at least partially removedor blurred due to the-fact that, after the application of graphite marksat or close to the printing station of a photographic copying machine,the web is caused to pass through one or more liquid baths before itreaches the severing station where the prints are separated from eachother. It has been found that one or more wet treatments greatly affectthe detectability of graphite marks so that they cannot be located witha requisite degree of reliability.

It was further proposed to expose'indicia onto the emulsion-coated frontside of a web of photographic paper and to use such indicia in the sameway as'graphite marks. The indicia are exposed adjacent to one or moreedge's'of the respective printsand are detectable by photoelectricscanning elements. Such indicia can be applied only to webs which are tobe subdivided into discrete prints of the type having a white marginsurrounding the image; however, they are evidently not suited forapplication to front sides of webs which are to"be subdivided to yieldso-called marginless or margin-free prints. Moreover, the presence ofindicia in the form of exposed and developed dark spots at the front ciais that they weaken the material of the web, especially during andimmediately after one or more wet treatments, so, that the web is likelyto tear in the region of slits or cuts during lengthwise transportthrough and after it issues from one or more liquid baths. Moreover,

such slits are observable at the front side of the web and affecttheappearance of the prints, especially if the distance between the slitand the respective edge of the print varies from print to print due toinsufficient accuracy of the severing operation. In other words, adiscriminating customer is likely to object to the presence of slits,especially if the position of slits is not identical on all prints of acomplete customer order.

The problems inconnection with the application of indicia are furtheraggravated if the webs of photographic paper or the like are coated orimpregnated with a film of synthetic plastic material. The plasticcoating does not retain graphite marks so that such webs are normallyprovided with indicia in the form of exposed symbolsand/or slits whichexhibit the aforediscussed drawbacks. Thus, there exists an urgent needfor apparatus which can be resorted to in the processing of films,photographic papers or the like in order to insure the formation ofdurable (lasting) and readily. detectable marks which do not exhibit thedrawbacks of .graphite marks, exposed marks, slits and/or similarpresently known indicia.

SUMMARY OF THE INVENTION An' object of the invention is to provide anovel and improved apparatus for providing webs of photographicf film,photographic paper or the like with readily detectable indicia which arenot likely to disappear or to become blurred or less pronounced duringfurther treatment of webs and which can be applied to such webs withoutaffecting the appearance of the webs and/or without affecting thequality of information which is stored on the webs.

Another object of the'invention is to provide an apparatus which can beutilized for the application of a wide variety of indicia each of whichcan be scanned for a different purpose and each of which can consist ofa single mark or a group of two or more properly arrayed' discretemarks.

An additional object of the invention is to provide the apparatus withone or more novel and improved indicia applying tools whose action isreproducible with a high degree of accuracy and which do not weaken thematerial of a web'during the application of indicia and/or do not affectthe quality of information which is stored on the webs.

A feature of the invention resides in the provision of identifyingselected portions of a web, e.g., a web of photographic paper having afirst side which is provided with a photosensitive layer and a secondside. The apparatus comprises means for subjecting the selected portionsof the web to the action of a deforming force which produces in one sideof the web indicia in the form of deformations (preferably lastingdeformations) each of which is sufficiently pronounced to be detectableby a mechanical scanning element, e.g., by a needle of the type used inrecord players. The selected portions are preferably spaced apart, asconsidered in the longitudinal direction of the web, and each thereofmay identify a discrete print of the web or the last print of a seriesof prints produced for a particular customer.

Each indicium 'may comprise one or more depressions, e.g., in the formof grooves, which are impressed into one side of the web by'a heated orunheated tool movable into and from engagement with the one side of theweb by an electromagnet, an eccentric or other suitable drive means. Thedepressions are preferably sufficiently lasting to be readily detectableby mechanical scanning means even if such mechanical scanning ispreceded by a transport of the web through one or more liquid baths, forexample, in an automatic developing machine. As a rule, the one side ofthe web is its second side, i.e., that side which is not coated with aphotosensitive emulsion but which may be coated with a film of syntheticplastic material.

Each of the depressions is preferably of identical configuration and/ordepth. For example, the depth of a depression in the form of a groovemay equal or approximate one-fifth of the thickness of the web. Groovesof such depth can be readily detected by a needle or analogousmechanical scanning means.

Each deformation may constitute or include a slit or cut in the one sideof the web; this is often desirable if the web is transported throughone or more liquid baths prior to mechanical scanning of its indiciabecause the liquid can penetrate into the material of the web to therebycause at least some swelling of material in the region of slits so thatthe indicia are even more readily detectable at the mechanical scanningstation. Each of the indicia can be tested for quality (e.g., for depth,length and/or other characteristics) prior to mechanical scanning. Suchtesting is preferably carried out immediately downstream of the stationwhere the indicia are being formed.

Each of the indicia may consist of two or more discrete deformations.and the deformations of each indicium are preferably spaced apart fromeach other through predetermined distances. For example, if eachindicium comprises two or more parallel grooves which are impressed intothe rear side of the web, the distance between each pair of adjoininggrooves may equal a predetermined distance and such grooves preferablyextend transversely of the longitudinal direction of the web. The webcan be,provided with indicia while it is in motion or while it is at astandstill between two successive stepwise movements.

The making of indicia each of which consists of two or more discretedeformations in the form of grooves or the like is desirable becausesuch indicia can be readily distinguished from accidental orunintentionally formed deformations in the form of scratches, cracks orthe like;

The novel features which are considered as characteristic of theinvention are set forth in particular in the appended claims. Theimproved apparatus itself, however, both as to its construction and itsmode of operation, together with additional features and advantagesthereof, will be best understood upon perusal of the following detaileddescription of certain specific embodiments with reference to theaccompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a fragmentary plan view ofthe rear side of a web of photographic paper which is provided withindicia in the form of groups of three parallel grooves each;

FIG. 2 is an enlarged fragmentary elevational view of the working end ofa tool which can be used to provide the web with indicia of the typeshown in FIG. 1;

FIG. 3 is a partly elevational and partly vertical sectional view of anapparatus which embodies the tool of FIG. 2;

FIG. 4 is an enlarged axial sectional view of a detail within thephantom-line circle IV of FIG. 3;

FIG. 5 is an enlarged fragmentary plan view of the rearside of a webwhich is provided with modified indicia;

FIG. 6 is an enlarged fragmentary partly elevational and partlysectional view of a tool which can be used for the making of indicia ofthe type shown in FIG. 5;

FIG. 7 is a schematic partly elevational and partly vertical sectionalview of an apparatus which embodies the tool of FIG. 6;

FIG. 8 is a plan view of a combination of two apparatus of the typeshown in FIGS. 3 or 7, further showing two testing devices which areinstalled downstream of the respective apparatus and serve to monitorthe condition or quality of freshly formed indicia.

FIG. 8a is a fragmentary sectional view as seen in the direction ofarrows from the line VIIIaVIIla of FIG.

FIG. 9 is a fragmentary partly elevational and partly vertical sectionalview of a third apparatus which constitutes a modification of theapparatus shown in FIG.

FIG. 10 is a diagram showing the length of intervals of contact betweena web and the tool during the making of indicia;

FIG. 11 is a fragmentary partly elevational and partly verticalsectional view of an apparatus which consti-' tutes a modification ofthe apparatus shown in FIG. 9, and further showing means for adjustablymounting the apparatus in a photographic copying machine; and

FIG. 12 is a plan view of the structure shown in FIG. 1 1.

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a greatly enlargedview of a portion of a web 1 which is provided with indicia (only oneshown) in the form of groups of several discrete marks 2. Each mark 2 isan elongated straight groove which extends transversely of thelongitudinal direction of the web I and is applied to the rear(uncoated) side of the web. The indicium shown in FIG. 1 is adapted tobe mechanically scanned by a suitable feeler, e.g.. a feeler similar tothe needle of a record player, which produces signals for actuation of asevering device (not shown) serving to sever the web across the framelines between neighboring prints. The distance between the marks 2 whichform an indicium is preferably small, for example, about 1 millimeter.The number of marks 2 which together constitute an indicium can beincreased above three or reduced to two or one. More than two marks arepreferred in order to enable a mechanical scanning device todiscriminate between an indicium and a scratch or crack in the rear sideof the web 1. Another safeguard against eventual actuation of thesevering means in response to detection of a scratch or crack is thefact that indicia consisting of two or more marks 2 are regularly spacedalong one marginal portion of the web 1. The scanning device including aneedle-like or otherwise configurated feeler can be readily designed todiscriminate between regularly distributed groups of marks 2 andnon-intentionally produced unevennesses at the rear side of the web.Each of the marks 2 shown in FIG. 1 is assumed to have a triangularcross-sectional outline, i.e., each such mark is assumed to be flankedby two narrow surfaces which make an acute, right or obtuse angle andmeet in the deepmost portion of the respective mark.

A tool 3 which can be used to provide the rear side of the web 1 withindicia of the type shown in FIG. 1 is illustrated in FIG. 2. The toolis provided with three parallel tooth-shaped projections or teeth 3aeach having a rounded tip and each having two flanks which, in theembodiment of FIG. 2, make an acute angle (e.g., an angle of about 60).The distance between the tips of the teeth 3a corresponds to thedistance between the deepmost portions of marks 2 of an indicium. Thetool 3 may be made of hardened tool steel or ofa metal exhibitingsimilar characteristics. Its teeth 3a undergo negligible wear, mainlydue to the relatively low speed of movement of the tool 3 with respectto the web 1 during the making of marks 2. This renders it possible toutilize a single tool for a relatively long period of time withoutaffecting the quality of marks 2. It is clear that, if desired, the tool3 can be altered to provide the web 1 with indicia in the form of two ormore rows of marks 2, in the form of marks which are staggered withrespect to each other, as considered transversely of the longitudinaldirection of the web 1, or which are distributed and/or configurated inany suitable manner other than that shown in FIG. 1. All marks 2 neednot have the same length, depth and/or width, and straight marks may begrouped with curved or otherwise configurated marks. The flanks of teeth3a on the tool 3 of FIG. 2 are preferably polished or otherwise treatedto a high degree of finish.

FIG. 3 illustrates a grooving or mark-forming apparatus which embodiesthe tool 3 of FIG. 2. The apparatus is assumed to be installed in acopying machine having a frame or housing F which carries an inverted U-shaped bracket or support 4 for an electromagnet 5. The electromagnet 5is installed at a level above a guide or support 6 for a web 1 which isassumed to be transported at right angles to the plane of FIG. 3. Theupper side of the guide 6 has a shallow recess whose width only slightlyexceeds the width of the web 1 so that the latter is held againstexcessive sidewise movement to thereby insure that the marks applied bythe projections 3a of the tool 3 are located at a predetermined distancefrom the right-hand marginal portion of the web. The guide 6 may beprovided with elastic tongues 8 or other suitable means for biasing theweb 1 against the upper side of the guide so that the plane of the webduring travel below the electromagnet 5 is located at a predetermineddistance from the tool 3 when the latter dwells in the retracted orinoperative position of FIG. 3.

The armature 5a of the electromagnet 5 carries a holder 9 for the tool3. As shown in FIG. 4, the holder 9 is a sleeve having two radiallyextending tapped bores 9a, 9b. The bore 9a receives a screw 10a whichserves to separably secure the holder 9 to the lower end portion of thearmature 5a. The bore 9b receives an elongated externally threaded pin10 having a rounded tip which can be received in a shallow notch 3b ofthe tool 3 to thus insure that the tool is located at a predetermineddistance from the plane of the web 1 in the recess of the guide 6 aswell as that the projections 3a are properly oriented with respect tothe longitudinal direction of the web. As mentioned above, the tool 3 isintended to provide the web 1 with indicia consisting of groups ofseveral elongated marks or grooves 2 each of which extends at rightangles to the longitudinal direction of the web. In order to preventaccidental angular displacement of the holder 9 and the tool 3 therein,the outer portion of the pin 10 extends into a vertical guide slot 4a ofthe bracket 4.

When the electromagnet 5 is energized, the armature 50 moves downwardly,as viewed in FIGS. 3 or 4, and propels the tool 3 toward the exposedrear (upper) side of the web 1 in the guide 6. The kinetic energy of thedescending tool 3 is selected with a view to insure that each of themarks2 formed by the projections 3a of the tool has a predetermineddepth, for example, 0.05 millimeter if the average thickness of the web1 is about 0.25 millimeter. Since the marks 2 are relatively shallow (ascompared with the average thickness of the web 1) the descendingprojections 3a are not likely to cause a pressure-initiated exposure ofthe photosensitive emulsion at the underside of the web 1. Thelikelihood of such exposure is further reduced due to the fact that thetool 3 is provided with several projections 30 so that the pressure towhich the rear side of the web 1 is subjected when the electromagnet 5is energized is distributed over a relatively large area. It is clearthat the armature 5a can be designed to move the tool 3 downwardly inresponse to each deenergization of the electromagnet 5.

The extent of penetration of the projections 3a into the rear side ofthe web 1 can be regulated and changed in a number of ways. For example,one can control the current which is needed to energize theelectromagnet 5. It is also within the purview of the invention toprovide one or more mechanical stops which physically arrest the tool 3in a predetermined lower end position when the tips of the projections3a are located at a predetermined distance from the upper side of theguide 6. The just discussed mechanical stop or stops can be designed toabut directly against the upper side of the web 1 in the guide 6 tothereby increase the area of that portion of the web which is subjectedto pressure in response to downward propulsion of the tool 3. Anadvantage of stops which bear against the web is that they cancompensate for fluctuations in the thickness of the web below theelectromagnet 5 to thus further reduce the likelihood of formation ofmarks 2 having different depths.

Accurate regulation of the minimum distance between the guide 6 and thetips of the projections 3a is desirable in most instances, not only toinsure the formation of marks 2 having identical depths, widths andlengths but also to reduce the likelihood of pressureinduced exposure.of the emulsion at the front side of the web 1 below the groovingstation.

FIG. 5 illustrates a portion of a web 1 which is provided with differentindicia each of which includes several parallel marks 1 1 in the form ofcombined slits and grooves 11 having varying widths and depths. Themarks 1 1 can be formed by resorting to a tool 12 of the type shown inFIG. 6. This tool is a wheel having three circumferentially extendingendless cutting or scoring projections or ribs 12a. The tool 12 can becaused to rotate relative to the web 1 in the recess of the guide 6 (seeFIG. 7) whereby each of its projections 12a forms one of the three marks11. The edge of each scoring projection 12a is preferably rounded asshown in the upper part of FIG. 6. The projections 12a need not severthe entire web 1; it is normally sufficient to insure that theprojections 12a penetrate through the synthetic plastic layer which isoften applied at least to the rear side of the web. When the web 1 isthereupon transported through one or more liquid baths, the liquidpenetrates through the slits of marks 11 in the synthetic plasticcoating and causes the material of the web to swell which contributes tothe ease of detection of indicia including the marks 11.

The apparatus of FIG. 7 employes'a wheel-shaped tool 12 of the typeshown in FIG. 6. This tool is preferably mounted in the same way as thegraphite wheel of a conventional marking apparatus. As shown, the tool12 is rotatably mounted on a shaft 12b which can be moved along anarcuate path by a pivotable displacing member 13 (e.g., the armature ofa rotary electromagnet) whereby the projections 12a of the tool 12 movetoward and mark the rear or upper side of the web 1 in the guide 6. Itis possible to dimension the tool 12 of FIG. 6 in such a way that it canbe installed as a substitute for the graphite wheel in a conventional(existing) copying machine. This reduces the overall cost for conversionof a conventional machine into a machine which can be used for thepractice of the present invention.

Apparatus similar to that shown in FIG. 7 (but using graphite wheels)are disclosed in German Offenlegungsschrift No. l,497,384. Thispublication discloses that the wheel which is being pivoted by thearmature 13 can be set in rotary motion during engagement with the web.Such rotation of a graphite wheel is considered necessary in order toproduce a clearly defined graphite mark. When the apparatus of FIG. 7pivots and rotates a tool of the type shown in FIG. 6, rotation duringcontact with the web 1 is advantageous because it insures that theprojections 12a of the tool are more likely to sever the aforementionedsynthetic plastic layer at the rear side of the web. Moreover, therotating tool 12 is more likely to remove a portion of the plastic layerto thereby further enhance the likelihood of swelling of the thus scoredweb during travel through one or more liquid baths.

As mentioned above, the mechanical scanning device which serves todetect indicia consisting of one or more marks 2 or 11 may compriseoneor more needles 49 mounted in a head similar to the tone head of arecord player. It is also within the purview of the invention to employa yieldably mounted blade which extends at right angles to the directionof lengthwise movement of the web 1 at the scanning station. The bladeis biased against the rear side of the web 1 in line with the row ofindicia and is caused to penetrate into an oncoming mark 2 or 11 tothereby cause the generation of a preferably electric signal byresorting to an inductance, capacitance, piezoelectric crystal 50 orother suitable transducer means. Such transducer means can be used withequal advantage to produce electric signals in response to displacementof a needle 49 (FIG. 8a), i.e., when the tip of the needle penetratesinto a mark 2 or 1 l.

FIG. 8 illustrates schematically certain parts of a copying machinewhich are used to provide the web 1 with two rows of indicia, namely, afirst row of indicia which must be scanned to generate signals servingto actuate a severing device serving to subdivide the web 1 into aseries of discrete prints, and a second row of indicia which must bescanned to generate signals serving to actuate one or more devices whichmust be actuated upon completion of a customer order. It is well knownto use a single elongated web for the making of prints which are to bemailed to several customers. The signals which are generated ondetection of second indicia are used to indicate that the printsobtained upon severing of the preceding portion of the web belong to afirst customer and that the next-following prints belong to a differentcustomer.

The apparatus 14 applies indicia which serve to actuate the severingdevice, and the apparatus 15 applies indicia at longer intervals becausesuch indicia serve to indicate the last of a series of prints belongingto a given customer. As sown, the two rows of indicia are applied todifferent marginal portions at the rear side of the web 1. v

The apparatus 14 and 15 are respectively followed by suitable testing ormonitoring devices l6, 17 (each having a needle 49 and a signaltransmitting element 50) which serve to examine the freshly appliedindicia for quality and to arrest the drive means for the web 1 when thedetected indicia are unsatisfactory. The testing devices 16, 17 can alsoserve to generate signals which are detected by the attendant whoexamines the indicia and adjusts the respective marking apparatus 14 or15 if the indicia are unsatisfactory. The generation of visible oraudible signals can take place simultaneously with stoppage of the drivefor the web I. It is .clear that the testing devices (especially thedevice 16) can also serve to produce signals in response to failure ofthe respective apparatus 14 or 15 to produce indicia.

It has been found that indicia of the type shown in FIGS. 1 and 5 arereadily detectable by relatively simple and inexpensive mechanicalscanning devices and that the likelihood of confusion withunintentionally produced indicia (such as scratches or cracks in therear side of the web 1) is remote, especially if each indicium consistsof two or more marks. As mentioned before, the likelihood of confusion(especially in the case of indicia which serve to generate signals foractuation of the severing device) is further reduced due to the factthat the indicia recur at regular intervals.

,The indicia which are produced by the apparatus 15 can be fed into acomputer which is designed to furnish debit notes to the customer or tothe dealer or which charges the account of a customer or dealer inaccordance with the number and size of prints. Also, the signals whichare furnished in response to detection of indicia produced by theapparatus'IScan be used to start an automatic collecting Operation forthe prints belonging to a customer or dealer. Such operation may include introduction of prints and the corresponding exposed and developedfilm or films into envelopes or other types of containers for shipmentto the dealer or customer.

The drive means for moving the web 1 at a constant speed or stepwisecomprises a takeup reel 75 (FIG. 8) and a motor 76 whose operation issynchronized with operation of the motor (not shown) which transports anexposed and developed film through the printing station where the imagesof successive film frames are projected onto the emulsion-coated frontside of the web 1.

FIG. 9 illustrates a marking apparatus which constitutes a modificationof the apparatus shown in FIGS. 3 and 4. The apparatus comprises anelectromagnet 18 which is mounted on a bracket 19 secured to the frame Fof the copying machine. The armature 21 of the electromagnet 18 ismovable up and down and its axis 20 coincides with the axis of the tool26 which is assumed to be identicalwith the tool 3 of FIGS. 3-4. Anupwardly projecting extension 121 of the armature 21 is provided withexternal threads, as at 21a, and meshes with a knurled nut 22 which canbe rotated to change the bias of a helical spring 23 reacting againstthe housing of the electromagnet 18 and urging the armature 21 upwardly,as viewed in FIG. 9.

That portion of the armature 21 which extends downwardly beyond thebracket 19 preferably consists of a heat-insulating material and carriesa heating device or cartridge 24 including one or more electric heatingcoils 25. The circuit of the illustrated coil 25 includes a suitablethermostat (not shown) which regulates the temperature of the heatingdevice 24 and hence of the tool 26 which is partially surrounded by theheating device. For example, the temperature of the heating device 24may be between 1 lO-l20C., preferably about l 15 C.

The lower portion of the armature 21 is further provided with tworadially outwardly extending coaxial pins 28 which extend into verticalslots 27a provided therefor in a sleeve 27. The sleeve 27 is biaseddownwardly, as viewed in FIG. 9, by a helical spring 30 which reactsagainst the bracket 19. The extent to which the sleeve 27 is movableaxially relative to the armature 21 or vice versa is determined by thelength of the slots 27a. The sleeve 27 is provided with external threads(not specifically shown) meshing with the internal threads of a cuppedhold-down device 29 whose axial position with respect to the sleeve 27can be adjusted with a high degree of accuracy in response to rotationrelative to the sleeve, The bottom wall of the hold-down device 29 has acentral opening 29a through which the deforming projections of the tool26can extend to engage the rear (upper) side of the web 33 on thesupport or guide 31. The web 33 is movable in a direction to the left orto the right, as viewed in FIG. 9.

The guide 31 includes an insert or anvil 32 which is hard enough toavoid permanent deformation of its upper side if such upper side isstruck by the working end of the tool 26 in the event that the tooldescends while the anvil is not overlapped by a selected portion of aweb 33. Eventual deformation ofthe upper side of the anvil 32 couldresultin exposure of the adjacent portion of the photosensitive layer atthe underside of the web 33 in response to pressure which develops whenthe armature 21 propels the tool 26 downwardly. The projections of thetool 26 extend at right angles to the plane of FIG. 9, i.e., at rightangles to the direction of lengthwise movement of the web 33.

The axial position of the hold-down device 29 relative to the armature21 is selected in such a way that the projections of the tool 26 remainslightly spaced apart from the upper side of the anvil 32 when thearmature 21 is caused to descend and reaches its lower end position.During a first stage of downward movement of the armature 21, the spring30 maintains the sleeve 27 in its lower, end position relative to thearmature so that the pins 28 are located in the upper end portions ofthe respective slots 27a. When the underside of the hold-down device 29reaches the upper side of the web 33 in the guide 31, the armature 21begins to move relative to the .parts 27, 29 and the pins 28 ,begin toadvance toward the lower end portions of the respective slots. 27a. Thedownward movement of the armature 21 is terminated when the pins 28enter the lower end portions of the respective slots 27a; the distancebetween the upper side of the anvil32 and the .tips of the projectionson the tool 26 is then determined by the selected axial position of thehold-down device 29 relative to the sleeve 27 and by the thickness ofthe web 33 between the parts 32, 29.

The diagram of FIG. 10 shows that the distance I1 ,which the tool 26must cover in a direction toward the guide 31 before the underside ofthe hold-down device 29 reaches the upper side of the web 33 in theguide 31 is about 4 millimeters. As the armature 21 continues todescend, the spring 30 begins to store additional energy and the tool 26moves relative to the hold-down device 29 toward engagement with theupper side of the web 33. The length of the interval t during which theprojections of the tool 26 actually engage and deform the web 33 is atleast 25 and preferably about 35 milliseconds. The interval 1,. denotesthe time which is needed to cause the projections of the tool 26 topenetrate deepest into the upper side of the web 33; the interval 1,,denotes the duration of withdrawal of the projections from the freshlyformed marks or grooves, and the interval t denotes the period of dwellof the projections of tool 26 in their lower end positions at a minimumdistance from the upper side of the anvil 32. It will be seen that t t,.t t Each of the intervals 1,. and 1,, is only a small fraction of theinterval 1 It has been found that the projections of the heated tool 26are much more likely to penetrate into and through the synthetic plasticfilm at the upper side of the web 33 than the projections of a cold(unheated) tool. In fact, the projections of the heated tool 26 melt theplastic film not later than upon completion of the interval t Suchheating of the tool 26 (by the heating device 24, 25 or by analogousheating means) renders it possible to produce in the web 33 permanentmarks even if the force with which the armature 21 urges the tool 26downwardly is very small. Also. and if the force which the armature 21applies to the tool 26 is the same as in an apparatus using an unheatedtool, the tool 26 is more likely to provide the upper side of the web 33with deeper permanent marks whose configuration does not change duringthe interval which elapses between the making of such marks and thetransport of marks to the station where the marks are mechanicallyscanned for the purpose of generating electric signals which initiatethe operation of the aforementioned severing device or the device ordevices for reception of signals which indicate detection of the lastprint of a customer order.

The heating of tool 26 brings about another important advantage, namely,the distribution of pressures in the material of the web which isstressed by a heated tool is much more uniform than in a web which issubjected to the action of an unheated tool. This insures that thepressures which are transmitted through the major part of the web 33 andall the way to the emulsion at its underside are rather small and cannotresult in pressure-induced exposure of the emulsion during the formationof marks. The temperature of the tool 26 need not be raised to themelting point of plastic material which coats the upper side of the web33 in the guide 31; nevertheless, the quality of the marks which areproduced with the tool 26 is much higher than that of marks which areformed by a cold or unheated tool. This is'attributed to the fact thatplastic deformation of the material of the web 33 constitutes a higherpercentage of the overall deformation than when the deformation iscaused by an unheated tool. Moreover,a mark which is produced by aheated tool is less affected by the fact that the web 33 must beconveyed through one or more liquid baths than a mark which is producedby an unheated tool. This insures that the marks can be readily detectedand that the detected marks are capable of initiating the generation ofsatisfactory electric signals in spite of repeated wetting of the webprior to arrival of marks at the scanning station. As a rule, thesharpness of marks which are produced by resorting to a heated tooldecreases negligibly subsequent to transport of the web through one ormore liquid baths. Such liquid baths are provided at the developingstation or stations through which the web 33 must be conveyed on its wayfrom the exposure station of the copying machine to the severingstation.

FIGS. 11 and 12 illustrate a presently preferred mode of adjustablymounting the improved marking apparatus in or on the frame of a copyingmachine. The apparatus can be installed in existing copying machines orduring assembly of new copying machines. The nature of mounting of theapparatus in a copying machine is preferably such that the installationof apparatus in an existing machine necessitates the drilling of a smallnumber of holes and/or relatively simple other operations which can beperformed by semiskilled workmen. The adjustability of the apparatus issuch that the tool 26 can be properly mounted with respect to the guide31 (not shown in FIGS. 11 and 12) even if the holes, welded seams and/orthe like are not machined or formed with a maximum degree of accuracy.

I The electromagnet 18 of the marking apparatus is secured to aplate-like horizontal support 48 which is separably and adjustablysecured to a sheet metal bracket 35 on the frame 34 of a copyingmachine. The coupling means comprises a centrally located screw 36 whoseshank passes through aligned bores of the parts 48, 35 and whose lowerend portion mates 'with a nut 39. The screw 36 is flanked by twoadjusting screws 37, 38 which respectively mesh with lock nuts 40, 41.The external threads of the adjusting screws 37, 38 mate with thethreads in tapped bores of the bracket 35. By rotating the screw 37 or38 relative to the bracket 35, the operator can cause the tip of thescrew 37 or 38 to move the adjacent portion of the upper side of thesupport 48 further away from the underside of the bracket 35. Once theoperator has selected a desired axial position of the screw 37 or 38,the lock nut 40 or 41 is applied to prevent unintentional changes in theinclination of support 48 relative to the horizontal portion of thebracket 35.

The upper portion or extension 121 of the armature 21 of theelectromagnet 18 shown in FIG. 11 carries two lock nuts 42, 43 whichflank the upper horizontal leg of a U-shaped yoke 44. The spring 23reacts against the housing of the electromagnet l8 and bears against thelower nut 43 or against the upper leg of the yoke 44 to immediately liftthe armature 21 as soon as the winding of the electromagnet 18 isdeenergized. The vertically extending web of the yoke 44 is guided in anopen slot 48a of the support 48 and the lower leg of the yoke 44 isconnected to the armature 21 below the support 48. The slot 48a preventsexcessive angular displacements of the yoke 44, armature 21 and tool 26so that the projections of the tool are invariably held in properorientation with respect to the longitudinal direction of the web, notshown in FIGS. 1 l and 12. The lower end portion of the armature 21extends into a bore 440 of the lower leg of the yoke 44. The position ofthe yoke 44 can be changed in the direction of the axis 20 by anappropriate adjustment of the axial positions of lock nuts 42, 43.

The heating device 24 for the tool 26 is mounted on the lower horizontalleg of the yoke 44 through the medium of an elastically deformablecarrier 45. In the illustrated embodiment, the carrier 45 comprises arelatively short tube 45a consisting of rubber or the like and twometallic disks 45b, 45c which are respectively adjacent to the upper andlower axial ends of the tube 45a. The heating device 24 is secured to aninsulating plate 46 which is affixed to the underside of the disk 45c.The axis of the carrier 45 preferably coincides with the axis 20 of theelectromagnet 18.

The guide 31, its anvil 32, the sleeve 27 and the holddown device 29 areomitted in FIGS. 11 and 12 for the sake of clarity.

The apparatus of FIGS. 11 and 12 can be mounted in a copying machine inthe following way: g

It is assumed that the vertical arm of the bracket 35 is parallel to thedesired direction (axis 20) of reciprocatory movement of the armature21. It is further assumed that the horizontal arm of the bracket 35 isnormally located in a plane which makes an angle of with the verticalarm of the bracket 35. If the axis 20 of the installed electromagnet 18is not exactly normal to the plane of the web in the guide 31 below thetool 26, the plate-like support 48 which is rigid with the housing ofthe electromagnet must be tilted about a horizontal axis whichintersects the axis of the screw 36. The nut 39 is loosened and theaxial position of the screw 37 or 38 is changed to insure that theinclination of the support 48 will change as soon as the nut 39 istightened again. The minimum distance between the projections of thetool 26 and the upper side of the anvil 32 in the guide 31 can bechanged by moving the yoke 44 up or down relative to the armature 21 andby thereupon tightening the lock nuts 42, 43 to fix the yoke 44 (andhence the heating device 24 and tool 26) in the newly selected position.As a rule, the position of the yoke 44 relative to the armature 21 willbe selected in such a way that the tips of projections on the tool 26remain slightly spaced apart from the upper side of the anvil 32 whenthe armature 21 reaches its lower end position. Minor deviations of thepositions of projections on the tool 26 relative to the upper side ofthe anvil 32 can be compensated for by the resilient carrier 45. Thiscarrier can compensate for the fact that a plane touching the tips ofall projections on the tool 26 is not absolutely parallel to the planeof the upper side of the anvil 32. The carrier 45 yields sufficiently toinsure that each projection of the tool 26 penetrates into the materialof the web to the same extent so that the configuration of allsimultaneously formed marks is identical.

The mounting of lock nuts 42, 43 at the upper end of the armatureportion 121 is desirable because such nuts can be readily reached in anexisting copying machine which is equipped with the improved markingapparatus.

It will be noted that the adjusting means 37, 38, 42, 43 enable anattendant to move the tool 26 in several directions, including up ordown and sideways, so as to insure that the projections of the tool willengage selected portions of the web as well as that all marks will havethe same depth, width and length.

The improved marking apparatus is susceptible of many additionalmodifications. For example, the electromagnet or 18 can be replaced withan eccentric driven by a motor which completes one revolution wheneverit receives a starting impulse. An advantage of such means for movingthe tool is that the length of intervals during which the projections ofthe tool deform the web can be selected with a high degree of accuracy.

As mentioned before, the illustrated indicia are but a few examples of alarge number of different indicia which can be applied to the web forthe purpose of generating signals which are used to actuate a severingdevice or to actuate one or more devices which must be actuated upondetection of the last print of a customer order.

Without further analysis, the foregoing will so fully reveal the gist ofthe present invention that others can, by applying current knowledge,readily adapt it for various applications without omitting featureswhich fairly constitute essential characteristics of the generic andspecific aspects of our contribution to the art and, therefore, suchadaptations should and are intended to be comprehended within themeaning and range of equivalence of the claims.

What is claimed as new and desired to be protected by Letters Patent isset forth in the appended claims.

1. Apparatus for identifying selected portions of a web of photographicpaper of the type having a first side provided with a photosensitivelayer and a second side, comprising guide means for supporting a web,whose temperature at least approximates the ambient temperature, so thatone side of a selected portion of the web remains exposed; a markingtool reciprocable with respect to said guide means between a retractedposition and an operative position in which a portion thereof penetratesinto the one side of the selected web portion in said guide meanswhereby said portion of said tool subjects the selected portion to theaction of a deforming force which produces in the one side of the web anindicium in the form of at least one recess which is sufficiently deepto be detectable by mechanical scanning means; and means for moving saidtool between said positions thereof.

2. Apparatus as defined in claim 1, further comprising means for movingthe web lengthwise so as to place successive selected portions of theweb into register with said tool.

3. Apparatus as defined in claim 1, wherein said means for moving saidtool comprises an electromagnet.

4. Apparatus as defined in claim 1, wherein said portion of said toolcomprises a plurality of projections each of which provides said oneside of the web with a discrete recess in said operative position ofsaid tool.

5. Apparatus as defined in claim 1, further comprising means forlimiting the extent of penetration of said portion of said tool into theone side of the web in said guide means so that each recess of anindicium has a predetermined depth.

6. Apparatus as defined in claim 1, wherein said means for moving saidtool comprises an electromagnet.

7. Apparatus as defined in claim 1, wherein said tool comprises a wheeland said means for moving said tool between said positions comprises arotary electromagnet.

8. Apparatus as defined in claim 7, wherein said electromagnet isarranged to rotate said wheel in said operative position of said wheel.

9. Apparatus as defined in claim 1, wherein said portion of said toolcomprises at least one tooth-shaped projection.

10. Apparatus as defined in claim 9, wherein said projection has twoflanks making an angle of substantially 60 and a rounded tip.

11. Apparatus for identifying selected portions of a web of photographicpaper or the like of the type having a first side provided with aphotosensitive layer and a second side, comprising guide means forsupporting a web so that one side of a selected portion of the webremains exposed; a marking tool movable with respect to said guide meansbetween a retracted position and an operative position in which aportion thereof penetrates into the one side of the selected web portionin said guide means whereby said portion of said tool subjects theselected portion to the action of a deforming force which produces inthe one side of the web an indicium in the form of at least onedeformation which is sufficiently pronounced to be detectable bymechanical scanning means; means for moving said tool between saidpositions thereof; means for moving the web lengthwise so as to placesuccessive selected portions of the web into register with said tool;and testing means for monitoring successively formed indicia prior tomechanical scanning.

12. Apparatus as defined in claim 11, wherein said testing meanscomprises means for producing signals in response to detection ofunsatisfactory indicia.

13. Apparatus for identifying selected portions of a web of photographicpaper or the like of the type having a first side provided with aphotosensitive layer and a second side, comprising guide means forsupporting a web so that one side of a selected portion of the webremains exposed; a marking tool movable with respect to said guide meansbetween a retracted position and an operative position in which aportion thereof penetrates into the one side of the selected web portionin said guide means whereby said portion of said tool subjects theselected portion to the action of a deforming force which produces inthe one side of the web an indicium in the form of at least onedeformation which is sufficiently pronounced to be detectable bymechanical scanning means; means for heating said tool; and means formoving said tool between said positions thereof.

14. Apparatus as defined in claim 13, wherein said heating meanscomprises a device for maintaining said tool at a temperature ofllO-120C.

15. Apparatus as defined in claim 13, wherein said heating meanscomprises means for maintaining the temperature of said tool within apredeterminedrange of temperatures. 7

16. Apparatus for identifying selected portions of a web of photographicpaper or the like of the type having a first side provided with aphotosensitive layer and a second side, comprising guide means forsupporting a web so that one side of a selected portion of the webremains exposed; a marking tool movable with respect to said guide meansbetween a retracted position and an operative position in which aportion thereof penev trates into the one side of the selected webportion in said guide means whereby said portion of said tool subjectsthe selected portion to the action of a deforming force which producesin the one side of the web an indicium in the form of at least onedeformation which is sufficiently pronounced to be detectable bymechanical scanning means; and means for moving said tool between saidpositions thereof, including means for maintaining said portion of saidtool in contact with the web in said guide means for an interval of atleast milliseconds.

17. Apparatus for identifying selected portions of a web of photographicpaper or the like of the type having a first side provided with aphotosensitive layer and a second side, comprising guide means forsupporting a web so that one side of a selected portion of the webremains exposed; a marking tool movable with respect to said guide meansbetween a retracted position and an operative position in which aportion thereof penetrates into the one side of the selected web portionin said guide means whereby said portion of said tool subjects theselected portion to the action of a deforming force which produces inthe one side of the web an indicium in the form of at least onedeformation which is sufficiently pronounced to be detectable bymechanical scanning means; means for moving said tool between saidpositions thereof; support means; and means for adjustably securing saidtool and said means for moving said tool to said support means so thatthe tool is adjustable in a plurality of directions with respect to saidsupport means.

18. Apparatus as defined in claim 17, wherein said guide means comprisesan anvil having a side adjacent to the other side of a selected portionof a web in said guide means, said adjusting means being arranged tochange the minimum distance between said portion of said tool and saidside of said anvil in said operative position of said tool.

19. Apparatus as defined in claim 17, whereinsaid tool is reciprocablebetween said positions thereof and said adjusting means comprises meansfor changing the inclination of said tool relative to said guide means.

20. Apparatusfor identifying selected portions of a web of photographicpaper or the like of the type having a first side provided with aphotosensitive layer and a second side, comprising guide means forsupporting a web so that one side of a selected portion of the webremains exposed; a marking tool movable with respect to said guide meansbetween a retracted position and an operative position in which aportion thereof penetrates into the one side of the selected web portionin said guide means whereby said portion of said tool subjects theselected portion to the action of a deforming force which produces inthe one side of the web an indicium in the form of a deformation whichis sufficiently pronounced to be detectable by mechanical scanningmeans; means for moving said tool between said positions thereof; andelastic carrier means interposed between said tool and said means formoving said tool between said positions thereof.

21. Apparatus for identifying selected portions of a web of photographicpaper or the like of the type having a first side provided with aphotosensitive layer and a second side, comprising guide means forsupporting a web so that one side of a selected portion of the webremains exposed; a marking tool movable with respect to said guide meansbetween a retracted position and an operative position in which aportion thereof penetrates into the one side of the selected web portionin said guide means whereby said portion of said tool subjects theselected portion to the action of a deforming force which produces inthe one side of the web an indicium in the form of at least onedeformation which is sufficiently pronounced to be detectable bymechanical scanning means; .means for moving said tool between saidpositions thereof; and a hold-down device arranged to engage the oneside of a selected portion of the web in said guide means, at least insaid operative position of said tool.

22. Apparatusas defined in claim 21, wherein said hold-down devicesurrounds said tool, at least in said operative position of said tool.

23. Apparatus as defined in claim 21, further comprising resilient meansfor biasing said hold-down device against the one side of the web insaid guide means in said operative position of said tool.

1. Apparatus for identifying selected portions of a web of photographicpaper of the type having a first side provided with a photosensitivelayer and a second side, comprising guide means for supporting a web,whose temperature at least approximates the ambient temperature, so thatone side of a selected portion of the web remains exposed; a markingtool reciprocable with respect to said guide means between a retractedposition and an operative position in which a portion thereof penetratesinto the one side of the selected web portion in said guide meanswhereby said portion of said tool subjects the selected portion to theaction of a deforming force which produces in the one side of the web anindicium in the form of at least one recess which is sufficiently deepto be detectable by mechanical scanning means; and means for moving saidtool between said positions thereof.
 2. Apparatus as defined in claim 1,further comprising means for moving the web lengthwise so as to placesuccessive selected portions of the web into register with said tool. 3.Apparatus as defined in claim 1, wherein said means for moving said toolcomprises an electromagnet.
 4. Apparatus as defined in claim 1, whereinsaid portion of said tool comprises a plurality of projections each ofwhich provides said one side of the web with a discrete recess in saidoperative position of said tool.
 5. Apparatus as defined in claim 1,further comprising means for limiting the extent of penetration of saidportion of said tool into the one side of the web in said guide means sothat each recess of an indicium has a predetermined depth.
 6. Apparatusas defined in claim 1, wherein said means for moving said tool comprisesan electromagnet.
 7. Apparatus as defined in claim 1, wherein said toolcomprises a wheel and said means for moving said tool between saidpositions comprises a rotary electromagnet.
 8. Apparatus as defined inclaim 7, wherein said electromagnet is arranged to rotate said wheel insaid operative position of said wheel.
 9. Apparatus as defined in claim1, wherein said portion of said tool comprises at least one tooth-shapedprojection.
 10. Apparatus as defined in claim 9, wherein said projectionhas two flanks making an angle of substantially 60* and a rounded tip.11. Apparatus for identifying selected portions of a web of photographicpaper or the like of the type having a first side provided with aphotosensitive layer and a second side, comprising guide means forsupporting a web so that one side of a selected portion of the webremains exposed; a marking tool movable with respect to said guide meansbetween a retracted position and an operative position in which aportion thereof penetrates into the one side of the selected web portionin said guide means whereby said portion of said tool subjects theselected portion to the action of a deforming force which produces inthe one side of the web an indicium in the form of at least onedeformation which is sufficiently pronounced to be detectable bymechanical scanning means; means for moving said tool between saidpositions thereof; means for moving the web lengthwise so as to placesuccessive selected portions of the web into register with said tool;and testing means for monitoring successively formed indicia prior tomechanical scanning.
 12. Apparatus as defined in claim 11, wherein saidtesting means comprises means for producing signals in response todetection of unsatisfactory indicia.
 13. Apparatus for identifyingselected portions of a web of photographic paper or the like of the typehaving a first side provided with a photosensitive layer and a secondside, comprising guide means for supporting a web so that one side of aselected portion of the web remains exposed; a marking tool movable withrespect to said guide means between a retracted position and anoperative position in which a portion thereof penetrates into the oneside of the selected web portion in said guide means whereby saidportion of said tool subjects the selected portion to the action of adeforming force which produces in the one side of the web an indicium inthe form of at least one deformation which is sufficiently pronounced tobe detectable by mechanical scanning means; means for heating said tool;and means for moving said tool between said positions thereof. 14.Apparatus as defined in claim 13, wherein said heating means comprises adevice for maintaining said tool at a temperature of 110*-120*C. 15.Apparatus as defined in claim 13, wherein said heating means comprisesmeans for maintaining the temperature of said tool within apredetermined range of temperatures.
 16. Apparatus for identifyingselected portions of a web of photographic paper or the like of the typehaving a first side provided with a photosensitive layer and a secondside, comprising guide means for supporting a web so that one side of aselected portion of the web remains exposed; a marking tool movable withrespect to said guide means between a retracted position and anoperative position in which a portion thereof penetrates into the oneside of the selected web portion in said guide means whereby saidportion of said tool subjects the selected portion to the action of adeforming force which produces in the one side of the web an indicium inthe form of at least one deformation which is sufficiently pronounced tobe detectable by mechanical scanning means; and means for moving saidtool between said positions thereof, including means for maintainingsaid portion of said tool in contact with the web in said guide meansfor an interval of at least 25 milliseconds.
 17. Apparatus foridentifying selected portions of a web of photographic paper or the likeof the type having a first side provided with a photosensitive layer anda second side, comprising guide means for supporting a web so that oneside of a selected portion of the web remains exposed; a marking toolmovable with respect to said guide means between a retracted positionand an operative position in which a portion thereof penetrates into theone side of the selected web portion in said guide means whereby saidportion of said tool subjects the selected portion to the action of adeforming force which produces in the one side of the web an indicium inthe form of at least one deformation which is sufficiently pronounced tobe detectable by mechanical scanning means; means for moving said toolbetween said positions thereof; support means; and means for adjustablysecuring said tool and said means for moving said tool to said supportmeans so that the tool is adjustable in a plurality of directions withrespect to said support means.
 18. Apparatus as defined in claim 17,wherein said guide means comprises an anvil having a side adjacent tothe other side of a selected portion of a web in said guide means, saidadjusting means being arranged to change the minimum distance betweensaid portion of said tool and said side of said anvil in said operativeposition of said tool.
 19. Apparatus as defined in claim 17, whereinsaid tool is reciprocable between said positions thereof and saidadjusting means comprises means for changing the inclination of saidtool relative to said guide means.
 20. Apparatus for identifyingselected portions of a web of photographic paper or the like of the typehaving a first side provided with a photosensitive layer and a secondside, comprising guide means for supporting a web so that one side of aselected portion of the web remains exposed; a marking tool movable withrespect to said guide means between a retracted position and anoperative position in which a portion thereof penetrates into the oneside of the selected web portion in said guide means whereby saidportion of said tool subjects the selected portion to the action of adeforming force which produces in the one side of the web an indicium inthe form of a deformation which is sufficiently pronounced to bedetectable by mechanical scanning means; means for moving said toolbetween said positions thereof; and elastic carrier means interposedbetween said tool and said means for moving said tool between saidpositions thereof.
 21. Apparatus for identifying selected portions of aweb of photographic paper or the like of the type having a first sideprovided with a photosensitive layer and a second side, comprising guidemeans for supporting a web so that one side of a selected portion of theweb remains exposed; a marking tool movable with respect to said guidemeans between a retracted position and an operative position in which aportion thereof penetrates into the one side of the selected web portionin said guide means whereby said portion of said tool subjects theselected portion to the action of a deforming force which produces inthe one side of the web an indicium in the form of at least onedeformation which is sufficiently pronounced to be detectable bymechanical scanning means; means for moving said tool between saidpositions thereof; and a hold-down device arranged to engage the oneside of a selected portion of the web in said guide means, at least insaid operative position of said tool.
 22. Apparatus as defined in claim21, wherein said hold-down device surrounds said tool, at least in saidoperative position of said tool.
 23. Apparatus as defined in claim 21,further comprising rEsilient means for biasing said hold-down deviceagainst the one side of the web in said guide means in said operativeposition of said tool.